<template>
  <button @click="sub">-</button>
  <span>{{ counter }}</span>
  <button @click="add">+</button>
</template>

<script>
import { reactive, toRefs } from 'vue'

export default {
  setup () {
    const state = reactive({
      counter: 1
    })
    const add = () => {
      state.counter++
    }
    const sub = () => {
      state.counter--
    }
    return {
      ...toRefs(state),
      add,
      sub
    }
  }
}
</script>

<style scoped>
button,
span {
  width: 30px;
  font-size: 28px;
  margin: 10px;
}
</style>
